Equipment for applying viscous liquids, such as molten adhesives, and especially equipment as that used to apply beads, ribbons or unitary deposits of the extruded adhesive in a desired under highspeed production conditions, is co for applying molten adhesives to materials such as flat sheets of paper or cardboard pac nonwoven woven fibrous material and polyurethane substrates in articles such as disposable diapers and in other sealing applications for a variety of products.
One particular type of adhesive generally termed "hot melt" is often used where there is a need for very short set up time between the a cation of the adhesive and the bonding together of the parts being adhered to each other. Typical hot melt adhesives, such as thermoplastic adhesives, are relatively viscous and are pumped through the nozzle of a spray gun module for application to the surface being sprayed in the form of a continuous bead or as intermittent unitary deposits.
In many high-speed packaging applications, the plurality of continuous beads or intermittent unitary deposits of molten adhesive are simultaneously applied to moving sheets of material through a number of spray gun modules, as discussed in U.S. Pat. No. Re. 27,865 assigned to Nordson Corp., the assignee of the present invention, which patent is incorporated in its entirety herein.
A principal disadvantage of this type of equipment has been the time consuming setup and adjustment procedure required at periodic intervals. When the number of gun modules and the lateral spacing between the beads of adhesive require changing or repositioning for different applications, the individual spray gun modules have to be removed and replaced on the fixed service manifold which receives the supply lines for a molten adhesive fluid and the operating air, as in the case of the U.S. Pat. No. Re. 27,865. This procedure is quite time consuming and requires the interruption of the continuous production facility at frequent intervals. Also, only the angular position of the individual modules could be adjusted in the U.S. Pat. No. Re. 27,865 and each adjustment was independent of the adjustment of an adjacent module. Therefore, the setup and accurate alignment of the modules was still a time consuming procedure. Moreover, repositioning the modules by angular adjustment, can affect the spray pattern of the adhesive. For example, when the swirl spray modules are aligned with respect to the surface being sprayed at an angle other than ninety degrees, the swirl pattern changes from circular to oval.